ORIENTED AND AGGREGATED PARTICLE OF ZIRCONIA MICROCRYSTAL AND MANUFACTURE OF ZIRCONIA PARTICLE OF ANISOTROPIC SHAPE OR FIBROUS ZIRCONIA

摘要

PURPOSE:To manufacture zirconia particles of anisotropic shape or fibrous zirconia by heat treating zirconia microcrystals formed from an aqueous soln. of a zirconium salt in an aqueous soln. of a strong alkali in the presence of zirconium hydroxide. CONSTITUTION:An aqueous soln. of a zirconium salt or a mixed suspension consisting of the soln. and zirconium hydroxide is heat treated at a relatively low temp. such as about 90-200 deg.C under an acidic condition of =7pH, and it is aged and hydrolyzed to form monoclinic zirconia microcrystals or oriented and aggregated particles of the microcrystals. The microcrystals are put in an aqueous soln. of a strong alkali such as KOH or NaOH, zirconium hydroxide is added as a source for supplying zirconia, and heat treatment is carried out at =90 deg.C. By the heat treatment, the zirconia microcrystals are preferentially grown in a specified direction to obtain zirconia particles of anisotropic shape, or fibrous zirconia is obtd. by well accelerating the growth.